"Mark L. J." <abejohno@gmail.com> wrote in message <ba35e7b1-e79a-47b4-8dd2-f902982f812d@googlegroups.com>...> ??? Error using ==> mpower> Matrix must be square.> Error in ==> triscastdmeshgrid10012013b at 6> F=1.10471*X^2*A+0.04811*B*(14.0+A);- - - - - - - - - - The error message is telling you what is wrong. You wrote X^2 where X is not a square matrix. If you were to write X*X you would also get an error message. If you want to simply square each element of X you should write X.^2.